The invention relates to a method for a compatible increase in resolution in television systems for black and white and color picture transmission wherein the luminance signal of a signal source is scanned line by line with line interlacing and is limited by a transmitter lowpass filter.
The state of the art is defined by the presently used black and white systems as well as the PAL, SECAM and NTSC color television systems and is illustrated in the book entitled "Fernsehtechnik" [Television] by R. Theile published by Springer Verlag, Berlin-Heidelberg-New York, 1973.
These present-day television systems are not ideal with respect to fidelity in the reproduction of the transmitted images. The major drawbacks are, in particular, insufficient detail resolution, annoying line flicker, line travel and 25 Hz flicker along the horizontal outlines.
New system uses, such as video text, screen text, still picture transmission, home terminals, etc. cause these drawbacks to become even more evident. For example, television grid displays are almost unsuitable for computer graphics or for information retrieval. Considering the long-term outlook, however, a uniform display technique for all these cited uses seems to be desirable.
Morever, the trend to ever larger and brighter screens puts greater demands on detail resolution and freedom from flicker. The demand for increased detail resolution is especially applicable to large screen reproductions, e.g. with the aid of projection devices or on large planar displays.